Duplicating material

ABSTRACT

A pressure sensitive duplicating material comprises upper and lower sheets. Each upper sheet on its rear side is provided with a color layer having a loosened structure and under writing pressure being selectively transferable to a lower or copy sheet only provided with a special adhesive layer. Said selective transferability can be deleted if an additional binder is applied to the color layer in certain areas, the additional binder filling interstices of said color layer.

United States Patent [191 Hoffmann et al.

[ Sept. 24, 1974 DUPLICATING MATERIAL [75] Inventors: Gerhard Hoffmann, Vienna,

Austria; Walter Schiitzner, deceased, late of Vienna, Austria by Lilly Schiitzner, heir; Ingrid Schiitzner; Peter Schiitzner, heirs, both of Vienna, Austria [73] Assignee: Kores Holding Zug AG, Zug, Switzerland [22] Filed: Apr.'25, 1972 [21] Appl. No.: 247,463

[30] Foreign Application Priority Data Apr. 28, 1971 Austria 3651/71 [52] US. Cl 117/15, ll7/36.2, ll7/36.4, 117/75 F, 117/75 P, 117/155 UA [51] Int. Cl B4lm 5/10 [58] Field of Search l17/36.2, 36.4, 15,75 F, 117/75 P, 155 UA [56] References Cited UNITED STATES PATENTS 2,382,828 8/1945 Staneslow 117/362 2,974,585 3/1961 Newman ll7/36,2 3,011,905 12/1961 Newman ll7/36.2 3,256,107 6/1966 Strauss ll7/36.4 3,364,052 l/l968 Martino... ll7/36.2 3,545,999 12/1970 Firth ll7/36.4 3,666,524 9/1970 Wright..... l17/36.4 3,684,550 9/1970 Newman 1l7/36.4

Primary ExaminerWilliam D. Martin Assistant ExaminerWilliam R. Trenor Attorney, Agent, or Firmllolman & Stern [5 7 ABSTRACT 4 Claims, No Drawings DUPLICATING MATERIAL BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to a duplicating material comprising a color layer, which under writing or typing pressure is selectively transferable to copy sheets provided with a special adhesive layer. It is an object of the present invention to inhibit the above-mentioned transferability in predetermined areas of the duplicating set.

In modern business practice duplicating form sets are increasingly being used. Duplicating systems making use of so-called selective ink transfer are particularly suitable for such form sets because their manufacture is simple and inexpensive. In such duplicating systems, the uppermost sheet to be written or typed upon is provided on the rear with a color layer, which under the writing or typing pressure is not transferable to ordinary paper but is transferable to papers which on the side facing the color layer are provided with a colorreceiving layer. This color-receiving layer acts substantially as an auxiliary adhesive. For such auxiliary adhesives numerous waxes are suitable, as well as plastic materials, such as polyethylene, polyisobutylene, vinyl polymers and others.

For as long as duplicating form sets have been used, it has been desired to restrict the transferability to certain areas. In prior duplicating systems, in which the color to be transferred had been applied by a printing process, it was relatively simple to apply the color to be transferred to those parts of the area of the top sheet only where a transferability was desired. This duplicating process is generally known as a carbon printing process but recently has become much less important owing to various disadvantages, such as ageing of the carbon layer, a tendency to stain the fingers, and formation of undesired copies.

In principle in a duplicating system using selective color transfer, blank areas could be provided by omitting in those areas in which copies are not desired the transferable color layer or the adhesive primer forming the receiving layer. Such layers can be made only by special coating equipment not available in a formprinting office. Only an endless coating of such webs will be economical, the layer either extending throughout the width of the web or being applied, at best, in strips which extend throughout the length of the web.

For this reason it has been desired'to conceive measures permitting an inhibition of the transfer subsequently, i.e. from the completely coated duplicating paper and to use, if possible, equipment which is available in a form-printing office. In this way, those areas in which a transfer is not desired should be provided with a resist. In accordance with the present invention, this is accomplished in that an additional binder is applied to the color layer in the areas to be provided with a resist.

The additional hinder or resist layer is desirably applied in such a manner that it at least partially fills the interstices of the color layer. The additional binder may consist, e.g., ofa wax. In this case a hot printing process is utilised to apply the wax. Alternatively, a filmforming material soluble in a volatile solvent may be used, such as polyvinylacetate, polyisobutylene, cellulose derivatives or the like substances. In this case it is recommendable to apply the additional binder by flexographic printing. Surprisingly it has been found that the additional binder may have the same composition as the auxiliary adhesive used as a receiving layer on the copy sheet. It is readily apparent that this fact permits the use of a single coating mixture and even the use of the same equipment to apply both the receiving layer and the covering resist layer. Only the plate cylinder has to be exchanged for the application of a resist layer in the desired pattern instead of a continuous receiving layer.

In this connection it is also known to provide a duplicating material comprising a color layer not transferable alone, which color layer is covered by a layer of adhesive plastics material. That layer of adhesive plastics material serves as an auxiliary adhesive and under the writing or typing pressure causes the color layer to be transferred to ordinary paper. It should be noted that the materials intended to be used as such auxiliary adhesives for a coating layer belong in part to the same class of substances as those which according to the invention are used as a resist to inhibit copying transfer. While the mechanism of this surprising behaviour cannot yet be fully explained, it is believed that the binder of the cover layer partly fills the pores between the binder particles in the color layer and thus increases the cohesion of the color layer. It is impotant for this reason that the additional layer be applied from a homogeneous solution or melt so that it can penetrate the surface of the color layer.

This can be accomplished by an increase of the temperature of the coating composition or by a change of its viscosity.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention will be explained more fully with reference to the following examples:

EXAMPLE I A duplicating set consisting of a top sheet, which also serves as an original, and an underlying sheet to receive the copy, is made as follows:

A. A coating mixture having the following composition is applied to the rear side of the top sheet:

4 percent by weight polystyrene 5 percent by weight stearin 10 percent by weight carbon black 81 percent by weight trichlorethylene B. The front side of the underlying sheet is coated with hot ozokerite (softening point C Sheet (A) will produce copies only on a prepared sheet (B) but does not transfer color to untreated paper.

If the color layer of sheet (A) is covered in discrete areas with a further layer (C) consisting of a mixture of percent by weight paraffin 20 percent by weight polyisobutylene (Oppanol B50 of Badische Anilin & Soda-Fabrik AG, Ludwigshafen, West Germany) which mixture is applied in a molten state; the transfer copying ability in the areas covered with this layer C will be entirely eliminated.

EXAMPLE 2 A color layer (A) as described in Example 1 is coated by printing in certain fields with a cover layer (C) using the following mixture:

90 percent by weight benzine (boiling range 60 90 percent by weight Oppanol B150 (a polyisobutylene having a higher molecular weight than Oppanol B50 described in Example l) When the solvent has evaporated, only the uncovered areas of color layer (A) will produce copies on a receiving sheet (B) as used in Example 1. No copies are formed under those areas of the color layer which are coated with cover layer (C).

EXAMPLE 3 A selectively transferable color layer (A) is formed by the application of the following mixture:

5 percent by weight ethyl cellulose percent by weight graphite 10 percent by weight kaolin 60 percent by weight acetone 10 percent by weight water The addition of water results in a controlled loosening of the color layer so that its cohesion is reduced to such an extent that under writing pressure and in contact with a surface coated with waxlike substances at the points where pressure is applied the layer separates entirely from its base and is transferred to the receiving layer of the lower sheet. A cover layer (C) having the same composition as the cover Layer (C) described in Example 1 is applied to the color layer (A) by hot printing The receiving sheet is provided with a layer (B) having the same composition as cover layer (C). In this case too transfer copies may be produced in areas only in which there is no cover layer (C) over the color layer (A).

EXAMPLE 4 A color layer (A) is made by the application of the following mixture:

5 parts by weight polyvinyl acetate (Movilith 50 of Farbwerke Hoechst AG, Frankfurt-on-Main, West Germany) 7 parts by weight lithol red (barium lake of an azo dyestuff) 18 parts by weight lead stearate 70 parts by weight kaolin 250 parts by weight acetone The mixture is applied to paper and dried.

To the resulting layer there is applied by printing with a coating composition as described in Example 2 a cover layer C consisting of polyisobutylene.

The copy sheet is coated with a color-receiving layer (B) which has the same composition as the cover layer (C). Copies can be produced only in those areas of the color layer (A) not provided with the cover layer (C).

EXAMPLE 5 A color layer (A) as described in Example 3 is covered with a cover layer (C) applied as a molten mixture having the following composition:

50 percent by weight polyethylene (AC6 of Allied Chemical Corporation, New York, U.S.A.)

50 percent by weight cetyl alcohol The copy sheet is provided with an adhesive layer (B) as described in Example 4.

In this case too. Copies are produced only in the areas devoid of a cover layer.

EXAMPLE 6 A color layer (A) as described in Example I is pro vided by flexographic printing with a cover layer (C) applied as a mixture of 15 percent by weight Movilith 5O (poly-'vinylacetate) 85 percent by weight alcohol The copy sheet is the same as in Examples 1 and 2. Transfer copies are produced only in the areas which are not provided with a cover layer (C).

EXAMPLE 7 A color layer (A) as described in Example 4 is provided in various areas with a layer (C) of ozokerite (softening point C) by hot printing (hot-spot). The copy sheet is covered with a layer (B) having the same composition as cover layer (C) so that it corresponds exactly to the receiving sheet of Example 1.

The mixtures mentioned in the Examples for the several layers (A), (B), and (C) may be used in combina tions other than those mentioned in the Examples. provided that the solubility of the resins and plastics materials for the color layer is taken into consideration in the selection of the solvent for the cover layer. Care must be exercised to prevent the situation in which the solvent for the cover layer attacks the binder for the color layer so strongly that the color layer is lifted off in the printing machine and soils the cylinders.

it is claimed:

1. A duplicating material comprising a color layer which has a loosened structure and is pressure selectively transferable to a receiving sheet which is provided with a special adhesive layer, the transfer of the color layer being inhibited in certain areas by a resist which is applied to the color layer in those areas in which a transfer of the color layer is to be inhibited, said resist at least partially filling the interstices of the color layer, with the result that blocked areas are provided on the color layer which will not transfer from one sheet to another.

2. A duplicating material according to claim 1, wherein the resist is a film-forming material which is soluble in volatile solvents.

3. A duplicating material according to claim 1, wherein the resist is a waxv 4. A duplicating material according to claim 3, wherein the resist has the same chemical composition as the adhesive layer provided on the receiving sheet. l= 

2. A duplicating material according to claim 1, wherein the resist is a film-forming material which is soluble in volatile solvents.
 3. A duplicating material according to claim 1, wherein the resist is a wax.
 4. A duplicating material according to claim 3, wherein the resist has the same chemical composition as the adhesive layer provided on the receiving sheet. 